Ekin Güran

Etlik City Hospital, Department of Anesthesiology and Reanimation, Ankara, Türkiye

Güran E. Anesthesia Machines and Principles. In: Kazancı D, editor. Anesthesiology Fast Review. 1^st ed. Ankara: Türkiye Klinikleri; 2025. p.535-542.

ABSTRACT

• Anesthesia machines evolved a great deal from Boyle’s trolley at the beginning of the 20th century to today’s computer-assisted anesthesia workstations utilizing enhanced safety and monitoring features.
• They deliver a controlled mixture of medical gases and inhalational anesthetics while continuously monitoring the patient’s vital signs and respiratory mechanics.
• The machine operates with high-, intermediate-, and low-pressure systems, ensuring the safe gas flow with adequate pressures before delivering it to the patient.
• Medical gases are supplied from backup cylinders or the hospital’s central pipeline systems via color-coded pipelines. Improper gas connections are prevented by additional safety features.
• Flowmeters regulate the gas flow into the machine, while vaporizers dispense volatile anesthetics.
• Ventilators and breathing circuits are part of the gas delivery system, which regulates oxygenation and carbon dioxide removal while delivering anesthetic gases.
• Modern anesthesia machines have several ventilation modes, including mandatory, assisted spontaneous, and synchronized ventilation, which provides flexibility for the different needs of the patient.
• Scavenging systems are used to remove anesthetic waste, to reduce pollution.
• Monitoring electrocardiography, blood pressure, oxygen saturation, end-tidal CO2, and anesthetic gas levels throughout the surgery are essential to ensure safety.
• Regular machine checks, including the automated self-tests, the two-bag test, and the tug test, are required to ensure proper operation and avoid equipment-related anesthetic risks.

Keywords: Anesthesia; Respiratory mechanics; Mechanical ventilators